Apparatus and method for transferring particulate material

ABSTRACT

An apparatus for transferring, at high speed and in a very effective and accurate manner, particulate material from a feeder into reservoirs of a moving endless surface, e.g. a drum, by use of a pressure means, e.g. a specific three-dimensional plate, for applying pressure onto said particulate material present between said plate and said moving endless surface, and then transferring the particulate material with said moving endless surface with reservoirs to a substrate; the apparatus and method being particularly useful for the production of absorbent structures for absorbent articles.

FIELD OF THE INVENTION

This invention relates to an apparatus for transferring, at high speedand in a very effective and accurate manner, particulate material from afeeder into reservoirs of a moving endless surface, e.g. a drum, by useof a pressure/guiding means, e.g. a specific three-dimensional plate,for applying pressure onto said particulate material present betweensaid plate and said moving endless surface, and guiding said particulatematerial into said reservoirs, and then transferring the particulatematerial with said moving endless surface with reservoirs to asubstrate; the apparatus and method being in particular useful for theproduction of absorbent structures for absorbent articles.

BACKGROUND TO THE INVENTION

Traditionally, absorbent articles such as diapers comprise an absorbentcore with water-absorbent (cellulose) fibers and particles ofsuperabsorbent polymer particle, also referred to as particles ofabsorbent gelling material (“AGM”), enclosed by a substrate material, orsupported by a substrate material and then closed by a further material,e.g. such as a nonwoven.

Absorbent articles with so-called profiled absorbent cores have beendeveloped, whereby certain regions of the article comprise more AGM thanother regions. In such instances, accurate deposition of AGM isimportant to obtain the required profile. Furthermore, in the case ofabsorbent cores with only small amounts of, or no, cellulose fibers(having thus AGM particles as the only liquid storage material) accurateAGM distribution is highly important.

Various approaches have been proposed for obtaining absorbent cores withprimarily AGM particles and for obtaining absorbent cores that have AGMparticles in a specific profile or distribution, such as a predeterminedpattern, thickness profile, or adjusting various components of themanufacturing apparatus that act in the machine direction (“MD”), orcross-direction (“CD”). These approaches include indirect printingmethods, whereby the AGM particles are taken up by a drum from a bulkstorage of AGM particles—said roll or drum having reservoirs on thesurface thereof, the number, size and position of which determining theamount and pattern of AGM granules taken up by the drum- and whereby thedrum then rotates towards a substrate such as a nonwoven, to thenrelease the AGM onto the substrate (carried by a moving surface).

Surprisingly, the inventors found that such proposed indirect printingprocesses are in some instances difficult to run at high speed, forexample at speeds of more than 800 ppm or more than 1000 ppm (parts(absorbent cores) per minute), in particular when fine particulatematerial is used and/or when small (and large quantities of) reservoirsare used. It has been found that at high speeds, the AGM particles arenot always satisfactorily dropped (e.g. from a feeder/hopper) into thereservoirs of the roll/drum. Reservoirs may only be partially filled,whilst at certain areas of the drum excess AGM may build up. If vacuum(in the roll/drum) is used to aid filling of the reservoirs, then thisAGM build-up may obstruct the vacuum suction and this it may furtherobstruct the filling of the reservoirs This thus may result in aninaccurate distribution of the AGM in the absorbent cores, or evendefects in the formed absorbent cores.

The inventors have now found an improved apparatus and method forproducing, even at high speed, (absorbent) structures comprisingparticulate (absorbent) material; said apparatus and method arefurthermore able to employ a moving surface (e.g. roll or drum) with alarge number of small reservoirs, whilst still delivering accuratefilling.

SUMMARY OF THE INVENTION

Aspects of the invention provide an apparatus (1), and method using suchapparatus, that includes a particulate material feeder (30) for feedingparticulate material to a first moving endless surface (40) (e.g. drum)with reservoirs (50), adjacent to said feeder, and including a means(e.g. three dimensional plate (10)) for guiding said particulatematerial and applying first and subsequent second pressures on part ofsaid particulate material (100), said first pressure substantiallyperpendicular to the process direction and subsequently said secondpressure being non-perpendicular to the process direction, as describedherein, to guide said material into said reservoirs (50); said means orplate (10) being typically connected to a pressure control means.

In a first embodiment the invention relates to an apparatus (1) formaking a structure that comprises particulate material (100) supportedor enclosed by a substrate material (110), including:

-   -   a) a particulate material feeder (30) for feeding particulate        material (100) to:    -   b) a first moving endless surface (40) with a direction of        movement (MD) (per surface area of said surface) and with a        plurality of reservoirs (50), said surface (40) being adjacent        said feeder (30), said first moving endless surface (40) and        reservoirs (50) thereof being for receiving said particulate        material (100) from said first particulate material feeder (30)        and for transferring it directly or indirectly to:    -   c) a second moving endless surface (200), being said substrate        material (110) or being a moving endless surface carrying said        substrate material (110), for receiving said particulate        material (100) directly or indirectly from said first moving        endless surface (40); and    -   d) a three-dimensional plate (10), for applying pressure on part        of said particulate material (100) and for guiding said        particulate material (100) into said reservoirs (50), said plate        (10) being positioned adjacent said feeder (30) and adjacent        said first moving endless surface (40), said plate (10) having a        first plate face adjacent said first moving endless surface        (40), said plate face having at least:        -   i) a first surface area (11) substantially parallel to said            first moving endless surface (40), said first area being for            (and capable of) applying pressure on said part of said            particulate material (100) when present between said first            surface area (11) and said first moving endless surface            (40);        -   ii) a second surface area (12) neighboring said first            surface area (11), positioned downstream from the first            surface area (11) (in MD), said second surface area (12)            being non-parallel to said first moving endless surface (40)            and leading from said first surface area (11) towards said            first moving endless surface (40), said first surface area            (11) and said second surface area (12) are connected to one            another, preferably under an angle, including a rounded            angle (e.g. curvature, as described herein) or straight            angle, and/or said second surface area (12) preferably            having an average angle with said first moving endless            surface (40) of between 10° and 80°.            In some embodiments herein the plate face has a third            surface area (13), neighboring said second surface area            (12), being downstream from said second surface area (12)(in            MD), said third surface area (13) being substantially            parallel to said first moving endless surface (40) and in            closer proximity thereto than said first surface area (11).

The invention also relates to a method for making a structure thatcomprises particulate material (100) supported or enclosed by asubstrate material (110), including the steps of

-   -   a) feeding a first particulate material (100) with a feeder (30)        to a first moving endless surface (40) with a plurality of        reservoirs (50), adjacent said feeder (30);    -   b) allowing flow of said particulate material (100), or part        thereof, into a volume space present between said first moving        endless surface (40) and a three-dimensional plate (10),        adjacent said feeder (30) and adjacent and opposing said first        moving endless surface (40); and contacting a part of said        particulate material (100) with said three dimensional plate        (10), said plate having a first plate face adjacent said first        moving endless surface (40), and said plate face having:        -   i) a first surface area (11) substantially parallel to said            first moving endless surface (40); and;        -   ii) a second surface area (12) neighboring said first            surface area (11), being downstream (in MD) from said first            surface area (11), said second surface area (12) being            non-parallel to said first moving endless surface (40) and            leading from said first surface area (11) towards said first            moving endless surface (40), said first surface area (11)            and said second surface area (12) are connected to one            another, e.g. under an angle, including a rounded angle            (i.e. curvature) or a straight angle; preferably said second            surface area (12) having an average angle with said first            moving endless surface (40) of between 10° and 80°.    -   c) applying a pressure with said plate onto at least a portion        of said particulate material (100) present between said first        plate face and said first moving endless surface (40), guiding        (or optionally forcing or pressurizing or pushing), said        material into said reservoirs (50);    -   d) transferring said particulate material (100) in said        reservoirs (50) of said first moving endless surface (40)        directly or indirectly to a second moving endless surface (200),        being, or carrying, said substrate material (110);    -   e) depositing said particulate material (100) onto said        substrate material (110).

Each of said first and second surface area have, in some embodiments, an(average) length dimension (in MD) of at least 2 mm; and/or a certainlength in MD relative to the distance between centre points ofneighbouring reservoirs, as described below.

Said pressure application step c) includes, in some embodiments herein,preferably: firstly applying a pressure, with said first surface area(11) of said plate (10), said pressure being substantially perpendicularto the direction of movement of the first moving endless surface (MD),thereby guiding, or optionally pushing, at least a first portion of saidparticulate material (100) into said reservoirs (50); and secondly,applying a pressure with said plate face's second surface area (12) saidpressure being non-perpendicular to the direction of movement of thefirst moving endless surface (MD), thereby guiding, or optionallypushing, at least a second portion of said particulate material (100)into said reservoirs (50).

The first moving endless surface (40) has for example a surface speed ofat least 4.5 m/s, or at least 6.0 m/s, or at least 7.0 m/s, or at least9.0 m/s.

Said particulate material (100) may have for example a mass medianparticle size of from 150, or from 200 microns, to 1000 or to 900microns, or from 300, to 800 or to 700 microns. It may be particulateabsorbent polymeric material, as described herein.

The reservoirs (50) may for example have a maximum depth (perpendicularto MD) of from 1.0 to 8.0 mm, or from 1.5 mm to 5.0 mm or to 3.0 mm(herein referred to as average maximum depth: maximum per reservoir, andaveraged overall all reservoirs (50), as further described below). Thereservoirs (50) may for example have an average maximum dimension (e.g.diameter) in MD (averaged over all reservoirs (50), maximum perreservoir) of up to 20 mm, or up to 10 mm, or up to 6 mm.

In a further embodiment herein, the invention provides an apparatus (1)for making a structure that comprises particulate material (100)supported or enclosed by a substrate material (110), including:

-   -   a) a particulate material feeder (30), said feeder (30) being        for feeding particulate material (100) to:    -   b) a first moving endless surface (40) with a direction of        movement (MD) (per surface area of said surface, as defined        herein) and with a plurality of reservoirs (50), said surface        (40) being adjacent said feeder (30), said first moving endless        surface (40) and reservoirs (50) thereof being for receiving        said particulate material (100) from said first particulate        material (100) feeder (30) and for transferring it directly or        indirectly to:    -   c) a second moving endless surface (200), being said substrate        material (110) or being a moving endless surface carrying said        substrate material (110), for receiving said particulate        material (100) directly or indirectly from said first moving        endless surface (40); and    -   d) a first pressure means being positioned adjacent said first        moving endless surface (40), for applying pressure on at least        part of said particulate material (100) and optionally on part        of said first moving endless surface (40), said pressure being        in a direction substantially perpendicular to the direction of        movement of said moving endless surface (MD) (per surface area        where said pressure is applied);    -   e) a second pressure means adjacent said first moving endless        surface (40) and adjacent said first pressure means, for        applying pressure on at least part of said particulate material        (100), said pressure (in an area) being in a direction        non-perpendicular to the direction of movement of said moving        endless surface (MD) in said area.

The invention also provides absorbent structures obtainable by themethod or with the apparatus (1) of the invention, as described herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a cross sectional (cross section taken along MD and alongthe direction perpendicular thereto; e.g. side view) view of a portionof an exemplary apparatus (1) of the invention.

FIG. 2 shows cross sectional (as above) view of a part of the apparatus(1) as shown in FIG. 1, showing an exemplary plate (10) and its platefaces.

FIG. 3 shows cross sectional (as above) view of an alternative apparatus(1) of the invention with an exemplary plate (10) and its plate faces.

FIG. 4 shows cross sectional (as above) view of an alternative apparatus(1) of the invention with an exemplary plate (10) and its plate faces.

FIG. 5 shows a cross sectional view of a further apparatus (1) of theinvention (cross section taken along MD and along the directionperpendicular thereto, e.g. along the line of gravity).

FIG. 6 shows a cross sectional view of a further apparatus (1) of theinvention (cross section taken along MD and along the directionperpendicular thereto, e.g. side view).

FIG. 7 shows cross sectional view (as above) of an alternative apparatus(1) of the invention with an exemplary plate (10) and its plate faces.

FIG. 8 shows cross sectional view (as above) of an alternative apparatus(1) of the invention with an exemplary plate (10) and its plate faces.

DETAILED DESCRIPTION OF THE INVENTION

Particulate Material

The particulate material (100) herein may be any material in particulateform, e.g. flowable in dry state, which includes particles, flakes,fibers, spheres, agglomerated particles and other forms known in theart.

In some embodiments herein, the particulate material (100) isparticulate absorbent (or: superabsorbent) material, and this materialis typically polymeric, and also known as particulate absorbent gellingmaterial, herein referred to as AGM. This refers to polymeric materialsin particulate form that can absorb at least 10 times their weight of a0.9% saline solution, i.e. having a CRC value of at least 10 g/g asmeasured using the Centrifuge Retention Capacity test of EDANA (EuropeanDisposables and Nonwovens Association), test method No. 441.2-02“Centrifuge retention capacity”. The particulate AGM herein may have ahigh sorption capacity, e.g. having a CRC of for example at least 20g/g, or at 30 g/g. Upper limits may for example be up to 150 g/g, or upto 100 g/g.

The particulate AGM may have a good permeability for liquid, forexample, having a SFC value of at least 10×10⁻⁷ cm³ s/g; or preferablyat least 30×10⁻⁷ cm³·s/g, or at least 50×10⁻⁷ cm³s/g 10×10⁻⁷ cm³s/g, orpossibly permeability SFC value of at least 100×10⁻⁷ cm³s/g, or at leasta SFC of 120×10⁻⁷ cm³ sec/g. This SFC is a measure of permeability andan indication of porosity is provided by the saline flow conductivity ofthe gel bed as described in U.S. Pat. No. 5,562,646, (Goldman et al.)issued Oct. 8, 1996 (whereby however a 0.9% NaCl solution is usedinstead of Jayco solution). Upper limits may for example be up to 350 orup to 250 (×10⁻⁷ cm³·s/g).

In some embodiments herein the polymers of said AGM are internallycross-linked and/or surface crosslinked polymers.

In some embodiments herein, the aprticualte material herein is absorbentmaterial comprising or consisting of particles of polyacrylicacids/polyacrylate polymers, for example having a neutralization degreeof from 60% to 90%, or about 75%, having for example sodium counterions, as known in the art, e.g. surface crosslinked and/or internallycrosslinked and/or post-crosslinked polyacrylic acid/polyacrylatepolymers.

In some embodiments herein, the particulate material (100) is in theform of particles with, a mass medium particle size up to 2 mm, orbetween 50 microns and 2 mm or to 1 mm, or preferably from 100 or 200 or300 or 400 or 500 μm, or to 1000 or to 800 or to 700 μm; as can forexample be measured by the method set out in for example EP-A-0691133.In some embodiments of the invention, the particulate material (100) isin the form of particles whereof at least 80% by weight are particles ofa size between 50 μm and 1200 μm and having a mass median particle sizebetween any of the range combinations above. In addition, or in anotherembodiment of the invention, said particles are essentially spherical.In yet another or additional embodiment of the invention the particulatematerial (100) has a relatively narrow range of particle sizes, e.g.with the majority (e.g. at least 80% or preferably at least 90% or evenat least 95% by weight) of particles having a particle size between 50μm and 1000 μm, preferably between 100 μm and 800 μm, and morepreferably between 200 μm and 600 μm.

The particulate material (100) herein may advantageously comprise lessthan 15% by weight of water, or less than 10%, or less than 8% or lessthan 5%. The water-content can be determined by the Edana test, numberERT 430.1-99 (February 1999) which involves drying the particulatematerial (100) at 105° Celsius for 3 hours and determining the moisturecontent by the weight loss of the particulate material (100) afterdrying.

The particulate AGM herein may be particles of AGM that are surfacecoated or surface treated (this not including surface-crosslinking,which may be an additional surface-treatment); such coatings and surfacetreatment steps are well known in the art, and include surface treatmentwith one or more inorganic powders, including silicates, phosphates, andcoatings of polymeric material, including elastomeric polymericmaterials, or film-forming polymeric materials.

Substrate

The (e.g. absorbent) structure producible with the apparatus (1) andmethod of the invention comprises a substrate, to receive theparticulate material (100). This substrate may be any sheet or webmaterial, in particular paper, films, wovens or nonwovens.

In some embodiments herein, the substrate is a nonwoven, e.g. a nonwovenweb; nonwoven, when used herein, refers to a manufactured sheet or webof directionally or randomly orientated fibers, bonded by friction,and/or cohesion and/or adhesion, excluding paper and products which arewoven, knitted, tufted, stitch-bonded incorporating binding yarns orfilaments, or felted by wet-milling, whether or not additionallyneedled. The fibers may be of natural or man-made origin and may bestaple or continuous filaments or be formed in situ. Commerciallyavailable fibers have diameters ranging from less than about 0.001 mm tomore than about 0.2 mm and they come in several different forms: shortfibers (known as staple, or chopped), continuous single fibers(filaments or monofilaments), untwisted bundles of continuous filaments(tow), and twisted bundles of continuous filaments (yarn). The fibersmay be bicomponent fibers, for example having a sheet-core arrangement,e.g. with different polymers forming the sheet and the core. Nonwovenfabrics can be formed by many processes such as meltblowing,spunbonding, solvent spinning, electrospinning, and carding. The basisweight of nonwoven fabrics is usually expressed in grams per squaremeter (gsm).

The nonwoven herein may be made of hydrophilic fibers; “Hydrophilic”describes fibers or surfaces of fibers, which are wettable by aqueousfluids (e.g. aqueous body fluids) deposited on these fibers.Hydrophilicity and wettability are typically defined in terms of contactangle and the strike through time of the fluids, for example through anonwoven fabric. This is discussed in detail in the American ChemicalSociety publication entitled “Contact angle, wettability and adhesion”,edited by Robert F. Gould (Copyright 1964). A fiber or surface of afiber is said to be wetted by a fluid (i.e. hydrophilic) when either thecontact angle between the fluid and the fiber, or its surface, is lessthan 90°, or when the fluid tends to spread spontaneously across thesurface of the fiber, both conditions are normally co-existing.Conversely, a fiber or surface of the fiber is considered to behydrophobic if the contact angle is greater than 90° and the fluid doesnot spread spontaneously across the surface of the fiber.

The substrate herein may be air-permeable. Films useful herein maytherefore comprise micro pores. Nonwovens herein may for example be airpermeable. The substrate may have for example an air-permeability offrom 40 or from 50, to 300 or to 200 m³/(m²×min), as determined by EDANAmethod 140-1-99 (125 Pa, 38.3 cm²). The substrate may alternatively havea lower air-permeability, e.g. being non-air-permeable, to for examplebe better detained on a moving surface comprising vacuum.

In preferred executions, the substrate is a nonwoven material, anonwoven web, for example of the SMS or SMMS type, and it may have aCD-extensibility or a MD-extensibility, for example of more the 20%, orfor example more than 100%, but for example not more than 200%. Theratio of MD-extensibility to the CD-extensibility is at a given load notmore than one to two.

Further exemplary absorbent structures and cores are described hereinbelow.

Apparatus

The apparatus (1) of the invention comprises at least the followingcomponents: a feeder (30) for feeding particulate material (100) to amoving endless surface with reservoirs (50); said moving endless surfacewith reservoirs (50), for receiving said particulate material (100) andtransferring it to a substrate; a three-dimensional plate (10) adjacentsaid surface and adjacent said feeder (30); and a support, typically asecond moving endless surface (110, 200), for carrying or transporting asubstrate, for receiving said particulate material (100) from said firstmoving endless surface (40) with reservoirs (50).

An exemplary apparatus (1) is shown in FIG. 1, showing the feeder (30),first moving endless surface (40) with reservoirs (50), and a secondmoving endless surface (200), e.g. substrate (110), or a substrate thatmay be supported on a second moving endless surface (200), whereby saidfirst moving endless surface (40) rotates and thereby transfers theparticulate material (100) from the meeting point adjacent the feeder(30) towards a transfer point where the particulate material (100) istransferred to said substrate.

The apparatus (1) may comprise additional components or modules,upstream and/or downstream from the feeder (30) and first moving endlesssurface (40). Each of these components, and optional additionalcomponents, are now described in detail

Feeder (30)

The feeder (30) herein is capable of holding the particulate material(100), typically in bulk quantities, and letting it flow to said firstmoving endless surface (40). The point or area where the particulatematerial (100) leaves the feeder (30) is herein referred to as meetingpoint or area.

The feeder (30) may have any form or shape. The feeder (30) may have acontainer portion, to hold the particulate material (100), e.g. having avolume of at least 1000 cm³, and a guiding portion, e.g. a pipe-shapesportion, having one or more walls (31) that guides the particulatematerial (100) from the container portion to the moving endless surface.In some embodiments it has a funnel shape, as shown for example in FIG.1, having a container portion and a pipe-shaped portion.

The wall(s) (31) of the guiding portion maybe a unitary with thecontainer portion, or a separate portion, connected to the containerportion.

In some embodiments, as exemplified as well in the figures, thethree-dimensional plate (10) described herein after, has a second plateface (14) with fourth surface area that forms a guide wall for theparticulate material (100), and it opposes a wall (31) from the feeder(30).

The feeder (30) has an opening (32), for allowing exit of said materialtowards the moving endless surface, said opening (32) having openingedges positioned adjacent the first moving endless surface (40), andtypically in proximity thereto. In some embodiments, as also exemplifiedin FIGS. 1 and 2, the opening (32) of the feeder (30) may be taken to bethe opening (32) of the pipe-shaped portion of the feeder (30),positioned adjacent (e.g. above) the first moving endless surface (40).

The average distance between said opening edges and said first movingendless surface (40) may be for example less than 10 cm, or less than 5cm, and it may for example be less than 2 cm or less than 1 cm, and forexample at least 0.1 mm, or at least 1 mm.

The opening (32) may have any form, including circular or oval; in someembodiments, the opening (32) is rectangular.

The guiding portion and/or the opening (32) of the feeder may have anaverage dimension in direction of movement (MD), indicated in FIG. 2 asYf, of for example at the most 140 mm, or for example at the most 80 mmor at the most 60 mm; and typically for some embodiments of theinvention related to specific preferred particle size particulatematerial (100) specified above, at least 10 mm.

In the direction perpendicular to the direction of movement, the opening(32) may have an average dimension about at least 60% of to the width ofthe first moving endless surface (40), or about equal to said width.

In some embodiments, the feeder (30) is positioned above said firstmoving endless surface (40), for allowing gravity to help to “feed” saidparticulate material (100) to said first moving endless surface (40).Hereto, an opening edge of the feeder (30) may be positioned exactlyabove the first moving endless surface (40) (0°), or, when the firstmoving endless surface (40) is curved, or even for example circular, asshown in the figures, it may be positioned above said surface, whichmeans at any position between 90° and −90° (e.g. between 9 o'clock and 3o'clock position), or in some embodiments between 60° and −60°, orbetween 30° and −30° (measured as angle between an distal edge of theopening (32) and the force line of gravity). FIG. 5 shows for example afeeder (30) positioned exactly above the first moving endless surface(40), whilst FIG. 1 shows a feeder (30) positioned at 30° position (11o'clock position).

In some embodiments, the side wall or walls (31) are (substantially)parallel to the force line of gravity, so that said particulate material(100) can flow freely to said first moving endless surface (40). This isfor example shown in FIG. 5.

In some embodiments, as shown in all Figures except FIG. 3, the feeder'scontainer portion is in contact with or close proximity with the plate(10), and said plate (10) (e.g. the plate's second plate face, withfourth surface area (14), as described herein after), forms a guidingwall (31) for the particulate material (100), together with the wall(s)(31) of (the guiding portion of) the feeder (30). Thus, said particulatematerial (100) may also fall along and typically in contact with asurface (e.g. the second plate face or fourth surface area (14)) of saidplate (10), described herein after. In this case, the opening (and Y f)is defined by the edge of the guiding means wall (31) and the edge ofthe plate's second plate face.

In another embodiment, said feeder (e.g. guiding portion) may have awall (31) that is in contact with a surface of the plate (10), e.g. withsaid second plate face with said fourth surface area (14), describedherein after; in some embodiments, the feeder (30) has then also a sidewall (31) in contact with and parallel to the plate's fourth surfacearea (14); such a feeder (30) and plate (10) arrangement is for exampleshown in FIG. 3. Said side wall may be (substantially) perpendicular tothe direction of movement (MD) of said surface (in the point of saidfirst moving endless surface (40) that is adjacent said wall).

First Moving Endless Surface (40)

The first moving endless surface (40) herein may be any moving surfacethat can rotate to provide a moving endless surface, for example it maybe a transporter belt or a cylinder or drum or print roll, as known inthe art, which can rotate and thus provide an endless surface.

The first moving endless surface (40) has a direction of movement ofsaid surface, herein referred to as MD. “Direction of movement (MD)” ofsaid first moving endless surface (40), is herein to be taken to be thedirection of movement in a certain point of said surface or the averagedirection of movement in a certain specified area of said surface, asspecified herein. Thus, for a curved, e.g. circular, first movingendless surface (40), the direction of movement in a certain point ofthe surface, or the average direction of movement of a certain area ofsaid surface, is herein determined by determining the tangent in saidpoint or the average tangent of an area (then, said tangent being theaverage direction of movement in said area). This is for example shownin FIGS. 7 and 8. Said tangent is, as shown, perpendicular to the radiusof curvature in said point or perpendicular to the average radius insaid surface area, respectively.

The first moving endless surface (40) is typically a rotating devicewith a certain radius, such as a cylinder or drum, as for example shownin the Figures. The radius of the first moving endless surface (40) maydepend on what structure is produced, and what size of structure isproduced, and for example how many structures are produced per cycle ofthe first moving endless surface (40), e.g. drum. For example, the drummay have a radius (65) of at least 40 mm, or of at least 50 mm; it maybe for example up to 300 mm, or up to 200 mm.

The first moving endless surface (40) may have any suitable width, butfor example a width (perpendicular to MD) corresponding (substantially)to the width of the structure to be produced; this for example be atleast 40 mm, or at least 60 mm, or for example up to 400 mm, or up to200 mm.

It may be useful that the first moving endless surface (40) has opposinglateral zones and a central zone therein between, along the wholesurface in MD, and said reservoirs (50) are only present in said centralzone. Then, the width dimensions of the surface may apply to the widthof the central zone instead.

It should be understood that for purpose of determination of propertiesof the first moving endless surface (40), such as the MD, the radius,the width of said first moving endless surface (40), the surface areawhere no reservoirs (50) are present (the area between reservoirs (50))is used for such determinations. This surface area between reservoirs(50) is herein referred to as “outer surface area” of said first movingendless surface (40). Thus, in some embodiments, the first movingendless surface (40) is a drum with a surface with reservoirs (50), saidreservoirs (50) protruding into said drum, and being surrounded by saidouter surface area.

The reservoirs (50) may have any dimensions and shape, includingcubical, rectangular, cylindrical, semi-spherical, conical, or any othershape. The first moving endless surface (40) comprises reservoirs (50)with a void volume that can be filled with particulate material (100).This may be any suitable number of reservoirs, but for example at least20 or at least 50.

The reservoirs (50) may be present as identical reservoirs (50), or theymay vary in dimension(s) or shape. They may be present in a pattern overthe surface of said first moving endless surface (40), or they may bepresent uniformly over said surface. The exact reservoir (50) pattern,dimensions etc. will depend on the required structure to be formed, butmay for example also depend on the particle size of the particulatematerial (100), process speed etc. In some embodiments at least 30% ofthe surface area of the first moving endless surface (40) or of saidcentral zone thereof, described above, comprises said reservoirs (50),preferably at least 40% or at least 50%.

The reservoirs (50) may be present as lines of reservoirs (50) in MD androws in CD, (the direction perpendicular to MD). Alternatively, theyreservoirs (50) may for example be present in so-called alternating rowsand/or lines (whereby alternating reservoirs (50) form a row and/orline).

The distance in MD between the centre point of a reservoir (50) (saidcentre point being in the plane of the outer surface of the first movingendless surface (40)) and the centre point of a neighboring reservoir(50) (in a line of reservoirs (50)) may for example be at least 3 mm, orat least 4 mm, or at least 6 mm, or for example up to 40 mm or up to 30mm or up to 20 mm. This may apply to all such distances betweenneighboring reservoirs (50) in MD, or this may be an average over allsuch distances.

The distance in CD between the centre point of a reservoir (50) (saidcentre point being in the plane of the outer surface of the first movingendless surface (40)) and the centre point of a neighboring reservoir(50) (in a row of reservoirs (50)) may for example also be as above.

Said lines may extend substantially parallel to, and equally spacedfrom, one another and/or said lines may extend substantially parallelto, and equally spaced from, one another.

In some embodiments, the MD dimension of a reservoir (50) may be (onaverage over all reservoirs (50) and/or for each reservoir; measuredover the outer surface of the first moving endless surface (40)) atleast 1 mm, or at least 2 mm, or at least 4 mm, and for example at themost 20 mm or at the most 15 mm. The CD dimension may be within the sameranges as above, or it may even be the same as the MD dimensions for oneor more or each reservoir.

The reservoirs (50) may have any suitable dept dimension, and it maydepend for example on the height of the first moving endless surface(40) (e.g. radius), the thickness/caliper of the desired structure to beproduced, the particle size of the material, etc. The maximum depth of areservoir (50) and/or of all reservoirs (50), and/or the average maximumdepth (average over all maximum depths of all reservoirs (50)) may forexample be at least 1 mm, or at least 1.5 mm, or for example 2 mm ormore, and for example up to 20 mm, or up to 15 mm, or in some embodimentherein, up to 10 mm, or to 5 mm or to 4 mm or to mm.

According to some embodiments herein, the reservoirs (50) may have adimension in MD (average; and/or all reservoirs (50)) of from 2 to 8 mmor from 3 mm to 7 mm; and the reservoirs (50) may have a maximum depthand/or average maximum depth of for example from 1.5 mm to 4 mm, or to 3mm.

The first moving endless surface (40) is adjacent the feeder (30) andadjacent the plate (10) and preferably adjacent said substrate, asdescribed herein. It rotates such that it passes the feeder (30), toreceive the particulate material (100) in its reservoirs (50), in ameeting point or area, to then carry said particulate material (100)(“downstream”) to a transfer point or area, where the particulatematerial (100) leaves said first moving endless surface (40), in someembodiments, directly to or towards said second moving endless surface(110, 200); said second moving endless surface (200) may be a movingsubstrate (110) or a substrate (110) on a moving support.

One possibility to hold the particulate material (100) in the reservoirs(50) may be a vacuum (60) applied to the inner side of the first movingendless surface (40), e.g. drum, in combination with suction holes in(the bottom) of the reservoirs (50), to thus apply the vacuum suctiononto the particulate material. The vacuum suction is for exampleexemplified with the arrows (60) and (61) in the Figures. The vacuum(60, 61) is for example released just before or at the transfer point,e.g. the point where the first moving endless surface (40) is adjacentand opposing said second moving endless surface (110, 200) (as shownwith arrow 62). The vacuum (60) may be any vacuum pressure such as forexample at least 10 kPa, or at least 20 kPa.

The vacuum (60) may be provided by providing a plurality of vacuumchambers in said first moving endless surface (40) (e.g. in itsinterior), where vacuum (60) can be applied or released (e.g. indicatedby arrow (62)) (connected or disconnected), depending on the positionthereof in the process, e.g. when the vacuum chamber reaches thetransfer point, the vacuum may be disconnected (62) and the particlescan flow from the surface to the substrate, whilst when said chamberreaches the meeting point where the particulate material (100) flowsfrom the feeder (30) to the reservoirs (50), the vacuum (60) is applied(connected).

Additional air pressure may be applied to said particulate material(100) close to or at the transfer point, to ensure that the materialflows from the reservoir (50) to the second moving endless surface (110,200).

In some embodiments, further described below, the plate (10) faceadjacent the first endless moving surface has a third surface area (13)in close proximity to and substantially parallel to said first movingendless surface (40), that aids the retention of the particulatematerial (100) in said reservoirs (50), since it serves as a “cover” ofsaid reservoirs (50). Thereto, said third surface area (13) may belarge, as described below, in order to retain said particulate materialin said reservoirs (50) up to or close to said transfer point. This isfor example exemplified in FIGS. 7 and 8.

Three-Dimensional Plate

The present invention provides improved reservoir (50) filling by use ofspecific pressure means. In some embodiments of the invention, a threedimensional plate (10) is therefore employed, said plate (10) beingpositioned downstream from the meeting point/area, and being presentadjacent said feeder (30) and adjacent said first moving endless surface(40). Thus, the feeder (30) is positioned before the plate (10), indirection of the process, e.g. in the direction of movement of the firstmoving endless surface (40) (MD). Thus, it should be understood that atleast part of the particulate material (100) contacts the first movingendless surface (40) typically prior to contacting the first surfacearea (11) of the plate (10).

The plate (10) has a “plate face” which is the surface of said plate(10) adjacent and (substantially) facing said first moving endlesssurface (40) (opposing it).

The plate (10) face comprises at least a first surface area (11) andsecond surface area (12) that are connected to one another under anangle, e.g. a “rounded angle”, as for example shown in FIGS. 1 and 2, ora straight (true) angle, e.g. with the angle as described below.

In some embodiments, as for example shown in FIGS. 1 and 2, said plateface is a curved side of the plate (10), comprises a first surface area(11), and a second surface area (12), connected to one another with acurvature, herein referred to also as “rounded” angle, with an average“angle”, as described herein below; when present, the third surface area(13) may also be connected to the second surface area with a curvaturewith an average are rounded angle, as described below.

In addition, or alternatively, the plate face may comprise first andsecond surface areas, connected to one another with an angle, e.g. viaan edge with an angle, as for example shown in FIG. 7; and for example athird surface area, for example connected to said second surface area(12) with an edge with an angle, as shown in FIG. 7.

However, in some embodiments it is preferred that the first and secondsurface areas, and/or when present said second and third surface areas,and/or, when present, said first and fourth surface areas, are (e.g.all) connected with one another under a “rounded angle”, e.g. acurvature, so that the connection between the surface areas forms acurvature, as for example shown in FIG. 7.

The plate face comprises a first surface area (11), that is opposed toand adjacent said first moving endless surface (40) and that issubstantially parallel to said first moving endless surface (40).

When stated herein that “the first surface area (11) is substantiallyparallel to the first moving endless surface (40)”, this means that; 1)said first surface area (11) is parallel to the opposing surface area ofsaid first moving endless surface (40) (which is the area where saidfirst surface area (11) overlaps said first moving endless surface(40)), as for example shown in FIGS. 1, 2 and 3; or 2) said firstsurface area (11) and said opposing surface area of said first movingendless surface (40) are positioned under and average angle of at themost 30° or in some embodiments herein typically at the most 20°, as forexample shown in FIG. 7. In the latter case, the first surface area (11)should be positioned such that the edge thereof closest to the feeder(30) (upstream edge) is further removed from the first moving endlesssurface (40), than the edge connected to the second surface (downstreamedge).

Irrespective of whether the first surface area (11) is parallel orsubstantially parallel to the opposing first moving endless surface(40), in some embodiments, it may be preferred that the first surfacearea (11) is an even surface, and/or a smooth surface.

In some embodiments, the distance between the first surface area (11)and the opposing area of the first moving endless surface (40) is onaverage less than 15 or less than 10 times the maximum or mean particlesize of the particulate material (100), but at least equal to at leasttwice or at least four times said mean particle size, and/or at leastone or at least twice the maximum particle size. In some embodiments,the average distance may vary depending on the amount of particulatematerial (100) present under the first surface area (11) of said plateface, as described herein below in more detail. Then, the above averagedistance may be applicable under a certain pressure, or it may be theaverage distance at the average operating pressure, for example at 2.5bar. In some embodiments, the average distance is equal to or more thanthe (e.g. average) maximum depth of the reservoirs (50), e.g. forexample at least 1.2 times or 1.4 or 1.5 times.

Said first surface area (11) of the plate face is in proximity to thefirst moving endless surface (40), defining a volume between said firstsurface area (11) and said first moving endless surface (40), whereinduring the process particulate material (100) is present. Said firstsurface area (11) then applies a pressure onto said particulate material(100), or part thereof, to guide (or optionally force, or push) it intosaid reservoirs (50). Said pressure and direction of pressureperpendicular to first surface area (11) is for example shown by thearrows in FIGS. 7 and 8. In some embodiments herein said pressureapplied by said first surface area (11) is substantially perpendicular(as for example shown in FIG. 7) or perpendicular (as for example shownin FIG. 8) to the direction of movement (MD) of said first movingendless surface (40).

When stated herein that the pressure applied by said first surface area(11) of said plate (face) on said particulate material (100) is“substantially perpendicular to the direction of movement” of said firstmoving endless surface (40), this means herein that the averagedirection of pressure of said first surface area (11) (taken to be thedirection perpendicular to the average first surface area (11)direction) is perpendicular to the average direction of movement of theopposing surface area of said first moving endless surface (40), or thatthat said average direction of pressure of the first surface area (11)is under an angle of at least 60°, or typically at least 70°, with saidaverage direction of movement of said opposing surface area.

In some embodiments herein, said first surface area (11) may be parallelto said first moving endless surface (40) that it opposes (overlaps); ifsaid first moving endless surface (40) is curved, having a certainradius, e.g. being a drum with a certain radius, the radius of curvatureof said first surface are may be about the same, e.g. within 20% orwithin 10% of one another. In some embodiments herein, the first surfacearea (11) is curved, having a radius of curvature identical to theradius of curvature of said first moving endless surface (40) (e.g. drumradius).

The plate face may have a width about equal to the width of the firstmoving endless surface (40), or the central zone thereof.

The first surface area (11) of the plate face may have a length oraverage length, in MD, of for example at least 2 mm, or at least 4 mm,or at least 6 mm or at least 10 mm.

Alternatively, or in addition the first surface area (11) may havelength in MD of at least equal to the dimension of the average distancebetween the centre points of neighboring reservoirs (50) in MD, asdefined herein, preferably at least 1.5 times said dimension of saiddistance, or at least 2 times said dimension of said distance or atleast 2.5 times said dimension of said distance.

Alternatively, or in addition the first surface area (11) may havelength in MD that is at least equal to the average reservoir dimensionin MD, as defined herein, preferably at least 1.5 times said dimension,or at least 2 times said dimension or at least 2.5 times said dimensionor at least 3 times said dimension.

When said first surface area (11) is connected to said second surfacearea (12) with a curvature, as described above, then said dimension ofsaid first surface area (11) is delimited by the centre line of saidcurvature, as for example shown in FIG. 3 as Y₁₁. The same applies forthe dimensions in MD of the second and third and fourth surface area(14), herein after.

The plate face also comprises a second surface area (12) neighboringsaid first surface area (11), positioned downstream from the firstsurface area (11) (in MD), said second surface area (12) beingnon-parallel to said first moving endless surface (40) and leading fromsaid first surface area (11) towards, but in one preferred example notcompletely to, said first moving endless surface (40), said firstsurface area (11) and said second surface area (12) are connected underan angle to one another, said second surface area (12) having an averageangle with said first moving endless surface (40) of between 10° and 80°(said angle being between said second surface area (12) and said firstmoving endless surface (40) defining the area where the particulatematerial (100) is present during the process); in some embodiments theangle is less than 60° or less than 50°. In some embodiments, the angleis at least 20° or at least 30°, or in some embodiments, at least 40°;such larger angle can be seen in FIG. 8.

In one preferred embodiment, the first surface area (11) is parallel tothe opposing first moving endless surface (40) and said second surfacearea (12) is under an angel as defined above.

The second surface area (12) can apply a pressure that isnon-perpendicular to the direction of movement of the first movingendless surface (40). When stated herein that the pressure applied bysaid second surface area (12) of said plate (face) on said particulatematerial (100) is “a pressure non-perpendicular to the direction ofmovement of the first moving endless surface (40)”, is meant that theaverage direction of pressure by said second surface area (12) (taken tobe the direction perpendicular to the average second surface area (12)direction) is under an angle of less than 60° with the average MD in thearea of said first moving endless surface (40) opposing (overlapped)said second surface area. Typically, the average pressure is however notparallel to MD, e.g. said angle is at least 10°.

The second surface area (12) may be a straight or curved surface area.It may be preferred to have a smooth surface.

The second surface area (12) of the plate face may have a length oraverage length, in MD, of for example at least 2 mm, or at least 4 mm,or at least 6 mm. Alternatively, or in addition the second surface area(12) may have length in MD of at least equal to the dimension of theaverage distance between the centre points of two neighboring reservoirs(50) in MD, as defined above, preferably at least 1.5 times saiddimension of said distance. Alternatively, or in addition the secondsurface area (12) may have length in MD that is at least equal to theaverage dimension of a reservoir (50) in MD, as defined herein,preferably at least 1.5 times said dimension.

The first surface area (11) and second surface area (12) are connectedunder an angle i.e. connected via an edge with a certain angle (as shownin FIG. 7 for example) or connected by a curved area/curvature with anaverage “angle”, as for example shown in all other Figures. For example,the angle or average “angle” between the first and second surface area(12) may be from 100° to 170°; or at least 120° or at least 130°, andpreferably less than 160° or less than 150°.

The plate face may have a third surface area, substantially parallel tothe first moving endless surface (40), as defined above for the firstsurface area (11); or, in some embodiments, parallel to said firstmoving endless surface (40), or under an (average angle of less than 10°or less than 5°.

The third surface area (13) is in close proximity, or optionallypartially in contact with, said first moving endless surface (40). Inany event the third surface area (13) of the plate face is closer tosaid first moving endless surface (40) than said first surface area (11)of the plate face.

The average distance between the third surface are and the first movingendless surface (40) may be less than a 2 mm, or less than 1 mm; in someembodiments, it may be less than 0.5 mm. Alternatively, or in addition,the average distance may for example be about equal or less than themaximum particle size of the particle material. For example FIG. 8 showshow the third surface area (13) is spaced from the first moving endlesssurface (40) such that some particulate material (100) may still bepresent in the space between the third surface are and said first movingendless surface (40), said average distance being for example (slightly)more than or about the mass mean particle size of the particulatematerial (100).

The third surface area (13) may have a length in (MD) of for example atleast 2 mm, or at least 4 mm, or at least 6 mm, or at least 10 mm, or atleast 20 mm or at least 30 mm.

As mentioned above, the third surface area (13) may serve as a “closure”for said reservoirs (50), to ensure said particulate material (100)remains in said reservoirs (50). The third surface area (13) may then befor example at least 4 times or at least 8 times or at least 12 timesthe 9 average) reservoir (50) dimension in MD, and/or of the dimensionof the distance between the centre points of two neighboring reservoirs(50) in MD, as above.

The plate is positioned adjacent and downstream of the feeder (30), sothat the plate can contact the particulate material (100) directly afterrelease thereof by the feeder (30) (to or towards the first movingendless surface (40)). The position of the plate in the apparatus (1) isthus to a large extend determined by the position of the feeder (30),e.g. by the position of the feeder (30) guiding portion and/or wall(s)(31). In some embodiments, the position of the plate (10) in theapparatus (1) may be such that the outer edge/curvature (15) of theplate face's first surface area (11) is positioned substantially abovethe first moving endless surface (40), e.g. directly above the feeder(30), or under and angle, as defined herein above, of for example 60° to−90° (3 o'clock) or to −60°, or 30° to −60° or −30°.

The plate may have a second plate face, not opposing the first movingendless surface, that comprises a fourth surface area (14), beingadjacent or neighboring or in close proximity or even connected to saidfeeder (30) (said fourth surface area (14) is thus not part of the plateface comprising said first, second and optional third surface area, but(a part of) another side of the plate (10), e.g. herein referred to assecond plate face).

The fourth surface area/second plate face are, typically directly,neighboring and hence connected to said first surface area (11), forexample under and angle, or curvature (15) with an average “angle” offor example at least 70° or at least 80°, and up to 110° or 100°, andfor example about 90°.

Said second plate face (14) or said fourth surface area (14) mayoptionally be contacting and guiding said particulate material (100)towards said first moving endless surface (40), as described above.

When the plate (10) is movable during the process, e.g. in responds tochanging pressure, the fourth surface area (14) may not be attached tothe feeder (30), but only in close proximity thereto.

The fourth surface area (14)/second plate face may be positioned to bean extension to a feeder (30)'s container portion, guiding theparticulate material (100) from the container portion towards the firstmoving endless surface (40), as shown in for example FIGS. 1 and 5.Alternatively, the fourth surface area (14)/second plate face may bepositioned to be an extension to a feeder (30)'s guiding portion, e.g.wall (31) and then the particulate material (100) is guided from thecontainer portion towards the first moving endless surface (40) by thefeeder wall (31) and then by the fourth surface area (14) of the plate(10), as for example shown in FIG. 6.

The fourth surface area (14)/second plate face may be substantiallyperpendicular to the direction of movement of the first moving endlesssurface (40) (MD) under that fourth surface area (14)/second plate face.

The fourth surface area (14) or second plate face may for example havean average height dimension (e.g. substantially perpendicular to thedirection of movement of the first moving endless surface (40)) of atleast 2 mm, or at least 4 mm, or at least 6 mm, or at least 10 mm or atleast 20 mm.

The (external) pressure applied by the plate (10) onto the particulatematerial (100), e.g. via the first plate face, may be a pressure causedby gravity; the plate (10) may thus for example have a weight of atleast 500 grams, or at least 750 grams, preferably at least 1000 grams,and in some embodiments, up to 5000 grams. In such cases, the plate (10)is position above the first moving endless surface (40), as describedabove. In addition, or alternatively, a pressure application means maybe connected to the plate (10) to apply the pressure as describedherein.

In some embodiments, the plate (10) applies a certain pressure on tosaid particles that is controllable, e.g. it can be set to be a constantpressure, or variable over time. This is herein referred to ascontrolled external pressure. In some embodiments, this pressure is keptsubstantially constant or in a set range. This pressure range orconstant pressure may be for example in the range of, for example, from1 to 4 bar, or from 1.5 to 3.5 bar or from 1.5 to 3 bar or to 2.5 bar.

In some embodiments, the plate (10) is connected to a pressure controlmeans, said pressure control means (20) being capable of:

-   -   sensing the pressure onto said plate (10) face by said        particulate material (100) and    -   responding thereto, e.g. by: adjusting the pressure or force of        said plate (10) (plate face) onto said particulate material        (100).

The pressure control means (20) may include a means to adjust theaverage distance between the first surface area (11) of the plate faceand the first moving endless surface (40), and/or means to change theexternal pressure.

The pressure control means (20) may be any means know in the art tomaintain a certain pressure or adjust a certain pressure, including ahinge, a spring, or in particular an actuator (20).

The actuator (20) may be such that i) it senses the pressure on saidplate (10) (face) by said particular material, and in response theretoii) effects and controls movement of the plate (10) towards or away fromsaid first moving endless surface (40).

Any actuator (20) as known in the art may be used; actuator (20) aretypically mechanical, pneumatic, hydraulic or electrical device thatperforms a mechanical motion in response to an input signal; in thepresent case, it may be preferred that the pressure onto the plate bythe particulate material (100) is the signal to the actuator (20), andthat said pressure signal is for example translated into (mechanical)movement of said plate (10).

In some embodiments, the pressure control means (20) is such that whenthe particulate material (100) exerts a certain too high pressure ontosaid plate (10), the plate (10) moves away from the first moving endlesssurface (40), e.g. the distance between said first and second, andoptionally third surface area and said first moving endless surface (40)increases. Thereby, the external pressure of the plate (10) may staysubstantially constant, e.g. as above.

This helps to avoids that too much particulate material (100) builds upunder the plate (10), and/or that the particulate material (100) getstoo compacted, to be guided into the cavities, or to be removed from theapparatus (1) as excess material.

Pressure Means:

In some embodiments, the apparatus (1) comprises a first pressure means,e.g. device, being positioned adjacent said first moving endless surface(40), and adjacent or incorporated in said feeder (30), for applyingpressure on at least part of, or part of, said particulate material(100), said pressure being in a direction substantially perpendicular tothe direction of movement of said moving endless surface (MD), asdefined herein below; and in some embodiments, substantially parallelwith the direction of gravity.

The apparatus (1) then also typically comprises a second pressure meansadjacent said first moving endless surface (40) and adjacent said firstpressure means, and positioned downstream there from, for applyingpressure on at least part of, or part of, said particulate material(100), said pressure (in an area) being in a direction non-perpendicularto the direction of movement of said moving endless surface (MD), asdescribed below.

Said second pressure means may have a pressure-applying surfacesubstantially non-parallel to the direction of movement of said firstmoving endless surface (40) (MD), and having for example an averageangle with said first moving endless surface (40) of between 10° and80°.

Said first pressure means may have a pressure-applying surfacesubstantially parallel to the direction of movement of said first movingendless surface (40) (MD), for contacting and applying pressure onto atleast part of said particulate material (100) when present between saidpressure surface and said first moving endless surface (40).

The properties and specifics of the apparatus (1) and the pressurecontrol means (20) are equally applicable to the present inventionregarding the above first and second pressure means. Furthermore, thepressure means may have any of the other properties or specificsspecified herein for the plate.

Furthermore, in some embodiments herein, the properties and specifics ofthe first surface area (11) of the plate (10) equally apply to the firstpressure means above, and the properties and specifics of the secondsurface area (12) of the plate (10) equally apply to said secondpressure means.

Second Moving Endless Surface; and Optional Further Apparatus Components(Units); Resulting Structures

The particulate material (100) is transferred by the first movingendless surface (40) to a second moving endless surface (110, 200). Thismay be for example a belt or drum, or this may for example be a movingsubstrate (110), such as a film (e.g. film web) or such as, in someembodiments herein, a nonwoven (e.g. nonwoven web). It may for examplebe a substrate (110) carried on a moving endless surface such as a beltor a drum. In some embodiments, the second moving endless surface (200)is a web of substrate (110) with another component, such as an adhesiveand/or particulate material (100).

The second moving endless surface (110, 200) may have the same surfacespeed as the first moving endless surface (40), or it may have adifferent speed. In some embodiments, it has a speed of at least 1000part per minute and/or a speed of at least 4.5 m/s, or at least 6 m/s,or at least 8 m/s.

The particulate material (100) transfers from the first moving endlesssurface (40) (i.e. the cavities thereof) to said second moving endlesssurface (110, 200) in the transfer point or area. The transfer point isthe point (e.g. line parallel to the width of the first moving endlesssurface (40)) where the particulate material (100) starts being releasedfrom the cavity and starts being transferred to the second movingendless surface (110, 200). The whole area over which the transfer takesplace is herein referred to as transfer area.

In some embodiments herein, the second moving endless surface (200) is asubstrate (110) carried on moving endless support, such as a roll, drumor belt. This support may comprise vacuum means and openings, throughwhich the vacuum can be applied to said substrate (110), to retain thesubstrate on said support.

In some embodiments, the first moving endless surface (40) rotates andthe second moving endless surface (110, 200) is for example placedpositioned substantially under the first moving endless surface (40) sothat the particulate material (100) can transfer in the transfer pointor area to said second moving endless surface (110, 200) by gravity. Thetransfer point may thus be at a parallel to the line of gravity, orunder an angel therewith from 60° to −60°, or from 30° to −30°.

The substrate (110) may comprise an adhesive, in order to, at leastpartially, adhere the particulate material (100) to the substrate (110).In order to better allow vacuum to be applied on the substrate (110)with adhesive, the adhesive may be applied in a pattern, whereby partsof the substrate (110) do not comprise adhesive and parts of thesubstrate (110) do comprises adhesive. The pattern may correspond to thepattern of the reservoirs (50) of the first moving endless surface (40).

After transfer of the particulate material (100) to the second movingendless surface (110, 200), said surface may move the particulatematerial (100) to further additional units (which may be part of theapparatus (1) of the present invention), to apply further materials tothe particulate material (100) and/or the substrate (110). This mayinclude one or more further adhesive(s), for example applied by afurther (downstream) adhesive unit, and/or a further substrate (110),applied for example by a further (downstream) rotating support carryinga further substrate (110), a cutting unit etc.

In some embodiments, the second moving endless surface (200) is asubstrate (110) (e.g. on a support) and after transfer of theparticulate material (100) to said substrate (110), the substrate (210)moves to a unit that applies an adhesive material, and/or athermoplastic material and/or an adhesive thermoplastic material, forexample in fibrous form, to cover the particulate material (100), orpart thereof. In another or additional embodiment, the substrate withparticulate material (210) moves to a unit that applies a furthersubstrate (110) onto the particulate material (100), or optionally ontosaid adhesive and/or thermoplastic and/or thermoplastic adhesivematerial.

Said further substrate (110) may comprise adhesive on the side thatcontacts the particulate material (100) (or optionally saidthermoplastic and/or adhesive and/or thermoplastic adhesive material),to better adhere said substrate (110) to said particulate material(100). In some embodiments, the substrate with particulate material(210) (e.g. as a layer) is moved to a further unit, where a secondsubstrate with particulate material (100) (e.g. as a layer), e.g. madeby an apparatus (1) of the invention in the manner described herein, issuperposed thereon, for example such that substrate (110) and furthersubstrate sandwich said particulate material (100), e.g. said twoparticulate material “layers”. In some embodiments, the substrate withparticulate material (210), made with an apparatus (1) of the inventionand the method of the invention, is moved to a further apparatus (1) ofthe invention, that transfers particulate material (100) onto saidsubstrate with particulate material (210), (optionally onto saidthermoplastic and/or adhesive and/or thermoplastic adhesive material).

The apparatus (1) of the invention may thus comprise one or more units,upstream and/or downstream of said first moving endless surface (40),such as adhesive application unit(s), and/or substrate applicationunit(s). Such adhesive application units may be selected from any typeknown in the art, in particle slot coating units and spray units.

The resulting substrate with particulate material (210) may thus be aweb of structures herein (optionally combined with any of the furthermaterials described above) and it may then move to a cutting unit, thatcuts the substrate with particulate material (210), e.g. web ofstructures, into individual structures, e.g. absorbent cores forabsorbent articles, or absorbent articles or partial absorbent articles.Such absorbent cores or partial absorbent articles may then be combinedwith further absorbent article components, described herein below, toform a final absorbent article.

The support of said substrate (110) may comprise a grid, having forexample plurality of bars extending along the direction of movement ofsaid second moving endless surface (110, 200), and extending(substantially) parallel to and (equally) spaced from one another;and/or a plurality of cross bars extending along the directionperpendicular to the direction of movement of said second moving endlesssurface (110, 200), and extending (substantially) parallel to and(equally) spaced from one another; said cross bars or bars forming thus“channels” between them; or if the cross bars and bars are both present,forming “indentations” between them. The reservoirs (50) of the firstmoving endless surface (40) may then correspond (in the apparatus/duringthe transfer process) with the islands or part of the channels and theparticulate material (100) may transfer from the reservoirs (50) intosaid channels or into said indentations. The support grid may be avented support grid with vacuum means, applying a vacuum between thebars and/or crossbars, and thus in the areas of the substrate (110)supported by the grid, forming the islands or channels.

In some embodiments herein, a coversheet material, in the form of a webmaterial, is placed over the particulate material (100) on said secondmoving endless surface (110, 200), after transfer, to cover saidparticulate material (100), and typically to enclose it between saidcoversheet and said substrate (110).

In some embodiments, the particulate material (100) is placed in alongitudinally (MD) extending portion of the substrate (110), leaving alongitudinal (MD) extending portion free of particulate material (100).Then, the portion free of particulate material (100) may be folded ontosaid particulate material (100), after transfer thereof, to provide acover thereof. In this embodiment, the substrate (110) is thus also acover sheet. A further coversheet may be used in addition, as specifiedabove.

The substrate (110) may be joined to itself or to a cover sheet or othercomponent, as described above, by any means, for example by ultrasonicbonding, thermo-bonding or adhesive-bonding, e.g. for example sprayedadhesive bonding. The bonding region between the coversheet and thesubstrate (110), or may for example be at least 1%, or at least 2%, orfor example at least 5%, but for example not more than 50% or no morethan 30% of the surface area of the substrate (110). Preferably, thebonding region comprises essentially no particulate material (100).

As mentioned above, a adhesive, and/or thermoplastic or thermoplasticadhesive material may serve to at least partially cover and at leastpartially immobilize the particulate material (100), for example anadhesive and/or thermoplastic or thermoplastic adhesive material infibrous form, e.g fibrous layer which is at least partially in contactwith the particulate material (100) and optionally partially in contactwith the substrate (110). The thermoplastic material may be a hot meltadhesive material. In accordance with certain embodiments, thethermoplastic (adhesive) material may comprise a single thermoplasticpolymer or a blend of thermoplastic polymers, having for example asoftening point, as determined by the ASTM Method D-36-95 “Ring andBall”, in the range between 50° C. and 300° C., or alternatively thethermoplastic adhesive material may be a hot melt adhesive comprising atleast one thermoplastic polymer in combination with other thermoplasticdiluents such as tackifying resins, plasticizers and additives such asantioxidants. The thermoplastic polymer may have a molecular weight (Mw)of more than 10,000 and a glass transition temperature (Tg) usuallybelow room temperature or −6° C.>Tg<16° C. In certain embodiments,typical concentrations of the polymer in a hot melt are in the range ofabout 20 to about 40% by weight. In certain embodiments, thermoplasticpolymers may be water insensitive. Exemplary polymers are (styrenic)block copolymers including A-B-A triblock structures, A-B diblockstructures and (A-B)n radial block copolymer structures wherein the Ablocks are non-elastomeric polymer blocks, typically comprisingpolystyrene, and the B blocks are unsaturated conjugated diene or(partly) hydrogenated versions of such. The B block is typicallyisoprene, butadiene, ethylene/butylene (hydrogenated butadiene),ethylene/propylene (hydrogenated isoprene), and mixtures thereof. Othersuitable thermoplastic polymers that may be employed are metallocenepolyolefins, which are ethylene polymers prepared using single-site ormetallocene catalysts. Therein, at least one comonomer can bepolymerized with ethylene to make a copolymer, terpolymer or higherorder polymer. Also applicable are amorphous polyolefins or amorphouspolyalphaolefins (APAO) which are homopolymers, copolymers orterpolymers of C2 to C8 alpha olefins. In exemplary embodiments, thetackifying resin has typically a Mw below 5,000 and a Tg usually aboveroom temperature, typical concentrations of the resin in a hot melt arein the range of about 30 to about 60%, and the plasticizer has a low Mwof typically less than 1,000 and a Tg below room temperature, with atypical concentration of about 0 to about 15%.

In certain embodiments, the thermoplastic (adhesive) material may be inthe form of fibers of an average thickness of about 1 to about 50micrometers or about 1 to about 35 micrometers and an average length ofabout 5 mm to about 50 mm or about 5 mm to about 30 mm.

The cover layer may comprise the same material as the substrate (110),or may comprise a different material. In certain embodiments, suitablematerials for the cover layer are the nonwoven materials, useful for thesubstrate (110).

Method

The present invention also relates to a method as described above and asclaimed herein. Any of the above described features of the apparatus (1)and functions and method steps thereof apply the method of theinvention. In particular, in said method, the pressure application stepc) includes for example: firstly applying a pressure, with said firstsurface area (11) of said plate (10), said pressure being substantiallyperpendicular to the direction of movement of the first moving endlesssurface (MD), thereby guiding (or optionally pushing) at least a firstportion of said particulate material (100) into said reservoirs (50);and secondly, applying a pressure with said plate face's second surfacearea (12) said pressure being non-perpendicular to the direction ofmovement of the first moving endless surface (MD), thereby guiding, oroptionally pushing, at least a second portion of said particulatematerial (100) into said reservoirs (50).

In said method, a third surface area (13) as described above, may guide,or optionally push, a third portion of said particulate material (100)into said reservoirs (50) and/or it may aid retention of saidparticulate material (100) in said reservoirs (50).

In the method, the pressure may be controlled by use of a pressurecontrol means, including an actuator (20), as described above.

The method and apparatus (1) herein may produce for example at least1000 part per minute (ppm, or at least 1100 or at least 1200; said“parts” being the individual structures described herein, e.g. forexample absorbent structures.

In the method herein, said first moving endless surface (40) may havefor example a surface speed of at least 2.0 m/s, or at least 3 m/s or atleast 4.5 m/s, or at least 6.0 m/s, or at least 7.0 m/s, or at least 7m/s. Alternatively, or in addition, the first surface area (11) may havea speed defined by parts per minute, of at least 500 parts per minute,or at least 1000 parts per minute. In one such embodiment, the firstmoving endless surface (40) is a drum, comprising cavities correspondingto one or two, preferably one (e.g. absorbent) structure herein.

The method herein may be particularly useful to make absorbentstructures (including: a web thereof that may then be divided, e.g. cut,into individual absorbent structures), whereby said particulate material(100) is AGM, with a mass median particle size of from 150 to 1000microns, or from 200 or 300 to 700 microns.

The method may employ the step to add a thermoplastic material, and/oradhesive material and/or thermoplastic adhesive material to saidsubstrate (110) prior to transfer of said particulate material (100)and/or to the said particulate material (100) and/or substrate (110)after said transfer, and/or the step to add further substrate (s) orcovering sheet(s) and/or to fold the substrate (110) and close thesubstrate (110) over said particulate material (100) and/or the step toadd a further substrate with particulate material (100) (210), asdescribed above.

Absorbent Cores and Absorbent Articles

The apparatus (1) and method of the invention are for example useful toproduce absorbent structures, such as acquisition layers and/orabsorbent cores for absorbent articles, or partial absorbent articles,for example the backsheet and core and optionally the topsheet, of sucharticle; and/or to produce absorbent articles.

“Absorbent article” refers to devices that absorb and contain bodyexudates, and, more specifically, refers to devices that are placedagainst or in proximity to the body of the wearer to absorb and containthe various exudates discharged from the body. Absorbent articles mayinclude diapers, including fastenable diapers and (refastenable)training pants; adult incontinence undergarments (pads, diapers)feminine hygiene products (sanitary napkins, panty-liners), breast pads,care mats, bibs, wound dressing products, and the like. “Diaper” refersto an absorbent article generally worn by infants and incontinentpersons about the lower torso so as to encircle the waist and legs ofthe wearer and that is specifically adapted to receive and containurinary and fecal matter. As used herein, the term “body fluids” or“body exudates” includes, but is not limited to, urine, blood, vaginaldischarges, breast milk, sweat and fecal matter.

As well known in the art, the absorbent core is the portion of thearticle that retains absorbed bodily fluids. The absorbent core hereinthus comprises the particulate material (100) that is an absorbentparticulate material (100) (as defined herein) disposed on a substrate(110), formed by the apparatus (1) and method herein. The absorbent coredoes not include an acquisition system, a top sheet, or a back sheet ofthe absorbent article, which are additional components of such absorbentarticles. The absorbent core is typically sandwiched between at least abacksheet and a topsheet. The absorbent cores herein may thus comprisetypically a further layer, e.g. a further particulate material (100) andsubstrate layer (110 or 210), coversheet, or a further layer being aportion of the substrate (110) folded over said particulate material(100), as described above. The absorbent core herein may compriseadhesive and/or thermoplastic material, as described above.

In preferred embodiments herein, the absorbent core, and optionally theabsorbent article, is “substantially cellulose free” is used herein todescribe an absorbent core or article, that contains less than 10% byweight cellulosic fibers, or less than 5% cellulosic fibers, or lessthan 1% cellulosic fibers, or no cellulosic fibers.

In certain embodiments, the absorbent structure or core herein maycomprise said particuale absorbent (polymeric) material, e.g. AGM, in anamount greater than about 80% by weight of the structure or absorbentcore, or greater than about 85% by weight, or greater than about 90% byweight of the absorbent core, or greater than about 95% by weight of thecore.

According to certain embodiments, the weight of absorbent particulatepolymer material 66 and 74 in at least one freely selected first squaremeasuring 1 cm×1 cm may be at least about 10%, or 20%, or 30%, 40% or50% higher than the weight of absorbent particulate polymer material 66and 74 in at least one freely selected second square measuring 1 cm×1cm. In a certain embodiment, the first and the second square arecentered about the longitudinal axis.

It has been found that, for most absorbent articles such as diapers, theliquid discharge occurs predominately in the front half of the diaper.The front half of the absorbent structure herein may thus comprise mostof the absorbent capacity of the core. Thus, according to certainembodiments, the front half of said absorbent structure herein maycomprise more than about 60% of the particulate material (100), e.g.AGM, or for example more than about 65%, 70%, 75%, 80%, 85%, or 90% ofthe total amount of particulate material (100), e.g. AGM.

The absorbent article herein may comprise in addition to an absorbentcore, a topsheet and backsheet, and for example one or more side flapsor cuffs. The topsheet or cuffs or side flaps may comprise a skin carecomposition or lotion or powder, known in the art, panels, includingthose described in U.S. Pat. No. 5,607,760; U.S. Pat. No. 5,609,587;U.S. Pat. No. 5,635,191; U.S. Pat. No. 5,643,588.

Preferred absorbent articles herein comprise a topsheet, facing thewearer in use, for example a nonwoven sheet, and/or an apertured sheet,including apertured formed films, as known in the art, and a backsheet,an absorbent core, having optionally a core coversheet facing the wearerin use.

The backsheet may be liquid impervious, as known in the art. Inpreferred embodiments, the liquid impervious backsheet comprises a thinplastic film such as a thermoplastic film having a thickness of about0.01 mm to about 0.05 mm. Suitable backsheet materials comprisetypically breathable material, which permit vapors to escape from thediaper while still preventing exudates from passing through thebacksheet. Suitable backsheet films include those manufactured byTredegar Industries Inc. of Terre Haute, Ind. and sold under the tradenames X15306, X10962 and X10964.

The backsheet, or any portion thereof, may be elastically extendable inone or more directions. The backsheet may be attached or joined to atopsheet, the absorbent core, or any other element of the diaper by anyattachment means known in the art.

Diapers herein may comprise leg cuffs and/or barrier cuffs; the articlethen typically has a pair of opposing side flaps and/or leg and/orbarrier cuffs, each of a pair being positioned adjacent one longitudinalside of the absorbent core, and extending longitudinally along saidcore, and typically being mirror images of one another in the Y-axis (inMD) of the article; if leg cuffs and barrier cuffs are present, theneach leg cuffs is typically positioned outwardly from a barrier cuff.The cuffs may be extending longitudinally along at least 70% of thelength of the article. The cuff(s) may have a free longitudinal edgethat can be positioned out of the X-Y plane (longitudinal/transversedirections) of the article, i.e. in z-direction. The side flaps or cuffsof a pair may be mirror images of one another in the Y-axis(longitudinal axis; MD axis) of the article. The cuffs may compriseelastic material.

The diapers herein may comprise a waistband, or for example a frontwaistband and back waist band, which may comprise elastic material.

The diaper may comprise side panels, or so-called ear panels. The diapermay comprise fastening means, to fasten the front and back, e.g. thefront and back waistband. Preferred fastening systems comprise fasteningtabs and landing zones, wherein the fastening tabs are attached orjoined to the back region of the diaper and the landing zones are partof the front region of the diaper.

The absorbent article may also include a sub-layer disposed between thetopsheet and the absorbent core, capable of accepting, and distributingand/or immobilizing bodily exudates. Suitable sublayers includeacquisition layers, surge layers and or fecal material storage layers,as known in the art.

Other suitable components of absorbent articles include acquisitionlayers. Suitable materials for use as the sub-layer may include largecell open foams, macro-porous compression resistant non woven highlofts,large size particulate forms of open and closed cell foams (macro and/ormicroporous), highloft non-wovens, polyolefin, polystyrene, polyurethanefoams or particles, structures comprising a multiplicity of verticallyoriented, preferably looped, strands of fibers, or preferably aperturedformed films, as described above with respect to the genital coversheet.(As used herein, the term “microporous” refers to materials that arecapable of transporting fluids by capillary action, but having a meanpore size of more than 50 microns. The term “macroporous” refers tomaterials having pores too large to effect capillary transport of fluid,generally having pores greater than about 0.5 mm (mean) in diameter andmore specifically, having pores greater than about 1.0 mm (mean) indiameter, but typically less than 10 mm or even less than 6 mm (mean).

The (absorbent) structure or core formed herein comprises in someembodiments a substrate with said particulate material (210), wherebysaid substrate (110) is C-folded to enclose said particulate material(100). In other words, the particulate material (100) may be depositedunto the substrate (110) and the substrate (110) may then be folded tocover the particulate material (100). Alternatively, or in addition, aseparate sheet material, or cover sheet, may be placed over theparticulate material (100) after it is deposited onto said substrate(110), to cover the particulate material (100). Such a coversheet may beany of the material described herein above as substrate (110) material,e.g. a nonwoven sheet or web.

Alternatively, or in addition, two or more of the substrates withparticulate material (210) deposited thereon may be produced and placedonto one another, to cover one another. Hereby, an additional coversheetmay be placed first onto the particulate material (100) on saidsubstrate, and then a further substrate with particulate material (210)may be placed thereon, typically such that said latter particulatematerial (100) contacts said coversheet.

Some embodiments of the invention relates to a pack comprising amultitude of at least five absorbent articles, as described below,comprising each an absorbent structure (herein referred to as absorbentcore) produced by use of the method of the invention and/or by use ofthe apparatus of the invention, typically at a line speed as describedabove. The apparatus and method of the invention are such that veryaccurate filling of the reservoirs and very accurate transfer isachieved, even at high speed. The resulting absorbent cores, including aweb of such cores that is subsequently separated into individual cores,are therefore substantially identical.

Of each of the absorbent article of the multitude of articles, comprisesan absorbent core obtained by use of the method or the apparatus (1) ofthe invention, and each core comprises particulatepolyacrylate/polyacrylic acid polymeric material, as described hereinabove, typically such crosslinked polymers, having internal and/orsurface crosslinking. The multitude may of 5 articles, or of course itmay be more than five absorbent articles, for example at least 10absorbent articles. Typically, within a pack, the articles areconsecutively produced articles. Thus, in some embodiments, theabsorbent cores of said multitude are consecutively produced absorbentcores, produced by the method and/or apparatus of the invention.

The pack may be any pack, of any shape, and made of any packagingmaterial, as known in the art, including a plastic bag, cardboard boxetc.

Each absorbent core comprises (in addition to said particulate polymericmaterial) a nonwoven substrate material (110) and an adhesive material,adhering said particulate polymers to said substrate material and/or toone another, as described herein. In some embodiments, more than oneadhesive material may be used. It may comprise more than one substratematerial, and/or addition core cover materials, e.g. nonwovens, asdescribed herein above. In some embodiments, the absorbent core mayconsist of said particulate material, adhesive material(s) and substratematerial(s), and optional additional core cover materials.

Each absorbent core has a length dimension (in MD) and a width dimension(CD; perpendicular to the MD direction), each absorbent core isdividable in at least 10 strips extending along the width (in CD) of thecore and each strips having a dimension in MD of 1.0 cm; the methodbelow describes how such strips can be obtained from an absorbent core.Each absorbent core has at least 10 such strips and each core has atleast 10 such strips that each have an “internal basis weight” of atleast 100 gsm, but preferably at least 150 gsm, or preferably at least200 gsm, said internal basis weight the basis weight of the particulatepolyacrylate/polyacrylic acid polymeric material or of said particulatematerial and adhesive material(s), when present, but excluding saidsubstrate material(s) and additional core cover materials.

For such multitude of absorbent articles, each having such an absorbentcore, the average relative standard deviation of the amount ofparticulate polyacrylate/polyacrylic acid polymeric material is 10% orless, or 7% or less, or 5% or less, or 3% or less; this is the averageover 10 relative standard deviations (% RSD, being average/standarddeviation*100), each of said 10 being the % RSD of 5 equal strips (asdefined below), each of which taken of one of the 5 articles, as definedand determined by the test method below. As set out below, the amount ofAGM can be expressed in meq (AGM) or translated into grams (AGM).

This may be equally determined and applicable for multitudes ofabsorbent articles of more than 5, e.g. 10 or more, as set out below.When more than 5 articles are present, then the above average % RSDapplies to at least 5 consecutive articles in the pack, but it may applyto more than 5 articles, or to more sets of 5 consecutive articles, orto all articles in the pack. Packs may in some embodiments comprise upto 100 articles, or up to 75 articles, or up to 50 articles.

The polyacrylic acid/polyacrylate polymeric material (AGM) herein maycomprise other ingredients, such as coating agents; in any event, and insome embodiments herein, if such additional agents (e.g. coating agents)comprise acid/base groups, these agents are typically present at a levelof less than 1% by weigth of the AGM, and hence neglectable in thedetermination of the average % RSD. In another embodiment herein, theabsorbent core comprises no other compounds that have acid or basecroups other than the polyacrylic acid/polyacrylate polymer particles.

Because the method of the invention and the apparatus of the inventionproduce such cores with very accurate particulate material transfer tothe substrate material, no lumps of access material are obtained. Hencereduced amounts of adhesive material may only be needed, for examplesuch that the weight ratio of said particulate polyacrylate/polyacrylicacid polymers to said adhesive material (in said core) is from 15:1, orfrom 20:1, or from 25:1, to 100:1, or to 40:1 or to 40:1. It should benoted for the purpose of the absorbent articles of the invention, thatthe adhesive material(s) generally do not comprise any significantamount of acid or base group containing components Separately, or inaddition, because the transfer of the particulate material is veryaccurate, the basis weight of the substrate material may be reduced, forexample such that it has a basis weight of 15 gsm or less, or preferably12 gsm or less, or 10 gsm or less.

The process herein is preferably a high speed process, as describedherein; therefore, said absorbent articles comprises typicallymachine-readable registration marks, for example comprised on saidsubstrate material, and/or on the topsheet, backsheet and/or any othercomponent of said absorbent article. Such registration marks, known inthe art, enable exact positioning of components of the a article duringthe manufacturing process with respect to said registration marks and/orto one another.

The amount of a particulate polymeric material (AGM) per strip and/orper surface area, e.g. the basis weight thereof, may vary along (MD);the absorbent core may be a so-called profiled core, whereby certainstrips have a higher (internal or AGM) basis weight than another strip.It may be profiled in thickness direction; and/or the core may alsoprofiled in CD direction, being a shaped core having a width dimensionthat varies, for example having a smaller width in the centre of thecore, than in the average width in the front quarter and/or back quarterof the product.

Method to Determine Average Relative Standard Deviation

In this method, samples containing polyacrylate/polyacrylic acid basedpolymeric material (herein referred to as AGM) are first reacted with aknown amount of HCl. An aliquot of the solution is then titrated to abromophenol blue indicator with a NaOH solution. The titration resultscan be expressed as the milliequivalents (meq) of the neutralized acidgroups of the AGM.

Of 5 absorbent articles of a multitude of absorbent articles (e.g. 5 ormore or 10 or more), the absorbent cores produced by themethod/apparatus of the invention are removed.

A first absorbent core is oriented such that the transverse (CD) edgethat is in the article towards the front (of the user, e.g. front waistof a diaper) is labeled top, and the opposite transverse end is labeledbottom. The transverse and longitudinal axes are determined (andoptionally marked on the core). The absorbent core is then cut intransversely extending (i.e. along full width) strips with an equaldimension in MD of 1.0 cm±0.01 cm; the last strip at the bottom may beless than 1 cm, but it in that case disregarded for this test.

A cutting die is used with a hydraulic press to section the core intosuch strips. The die is manufactured such that it is able to cut stripsover the entire length (MD) and width (CD) and thickness of the core.The die is placed on an even surface (work bench) with its cuttingblades facing upward, and the core is laid across the die centered alongits transverse and longitudinal axes. A 0.25 inch Lexan plate with MDand CD dimensions larger than the die is placed on top of the core andthen the assembly is placed in the hydraulic press and cut. The stripsremain contained within the die until analysis to ensure that no AGMparticles are lost. Each strip is labeled with a consecutive number (1at top, 2, 3, 4, etc).

Each strip has thus a MD dimension of 1.0 cm, but the strips may havedifferent (average) widths (average per strip). For the purpose of theinvention, there are at least 10 strips per core.

For this first absorbent core, the “internal basis weight”, as definedabove, per strip is determined, by determining for each strip of saidfirst core the surface area of said strip (1.0×CD dimension), and thenremoving the substrate material(s) (and other core cover materials, ifpresent), as described herein, to obtain only the material(s) inside theabsorbent core, i.e. the particulate polyacrylic acid/polyacrylatepolymeric material transferred by the process/apparatus of the inventionand optional adhesive material(s), if present. The weight of thismaterial(s) is determined per strip, and then the “internal” basisweight per strip can be calculated (being the weight of said polymericmaterial and optional adhesive material per surface area of the strip).

Then, the 10 strips with highest “internal; basis weight” are determinedfor said first absorbent core. For the purpose of this test and thisinvention, there should be at least 10 strips that have an internalbasis weight of at least 100 gsm (or preferably at least 150 gsm or atleast 200 gsm as described herein above). The other strips (if any) aredisregarded for the titration test below.

Said 10 strips are then submitted to the titration, described below.(For example strips 4, 5, 6, 7, 8, 9, 10, 12, 14, and 15.)

The remaining 4 absorbent cores of the remaining (e.g. selected) 4absorbent articles (of the multitude) are each separately cut with thedie exactly as set out above for the first absorbent core. Then, perabsorbent core, the same strips as said 10 strips with highest internalbasis weight are separately removed from the die and separatelysubmitted to the titration method below. (For example strips 4, 5, 6, 7,8, 9, 10, 12, 14, and 15, per core). Thus a total of 50 strips areobtained and separately submitted to titration.

Titration Method:

A 50 mL certified digital burette (e.g. Digitrate, Jencons Scientific,Bridgeville, Pa., or equivalent) is used for the titration. 0.1N HCl and0.1N NaOH solutions are used (Baker Analyzed certified volumetricsolutions; J. T. Baker, Phillipsburg, N.J.).

An individual strip is removed from the die placed into a 400 mL beakerand the substrate material(s) and optional other core cover materialsare removed, ensure no loss of AGM during this transfer or substrateremoval takes place. The remaining sample is herein referred to as“AGM”.

Using a Class A volumetric pipet, 250 mL of 0.1N HCl acid is added, theAGM is submerged and soaked with stirring for 30 minutes. Then, this isfiltered through a Whatman #4 filter paper into another 350 mL beaker.Using a Class A volumetric pipet, 25 mL aliquot of the filtered solutionis pipeted into a 50 mL beaker. Four drops of 1% bromophenol blueindicator (w/w in deionized water) is added, and the solution istitrated with 0.1N NaOH to a blue endpoint. The volume of titrant isrecorded to ±0.01 mL.

Each of the strips above (in total 50) is measured in like fashion.

Millequivalents of the neutralized AGM acid groups can be calculated perstrip as:meq(AGM)=2.5 meq(HCl)−[mL 0.1N NaOH*0.1 meq/1 mL]

This value in meq (AGM) can be translated into grams (AGM), as known inthe art, if desired

Then, the standard deviation over 5 strips of same number (e.g. thestrips no. 4 of the 5 cores) can be determined and the relative standarddeviation (% RSD, being average/standard deviation*100) between saidequal strips (e.g. no. 4) of 5 articles.

This is determined for each set of 5 strips of the same number, toobtain a total of 10 standard deviations and 10 relative standarddeviation (e.g. for strips 4, 5, 6, 7, 8, 9, 10, 12, 14, 15).

Then the average of said 10 relative standard deviations (% RSD) iscalculated and reported as “average relative standard deviation”(average % RSD), as claimed herein. For the purpose of the invention,this should be 10% or less, but preferably 7% or less, or 5% or less.

The above test may be done for any multitude of absorbent articles ofthe invention, by taking 5 consecutive articles and cores thereof of apack; the test may also be done in the same manner as set out above formore than 5 articles.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

It should be understood, for the purpose of the invention, that theFigures are not to scale and that furthermore the dimensions of theexemplified apparatus and elements thereof, the dimensions of theparticulate material, and said dimensions relative to one another, asdepicted in the Figures are not intended to reflect the true dimensionsof said elements or particulate material, or relative dimensionsthereof, unless stated otherwise.

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A method for making a structure that comprisesparticulate material supported or enclosed by a substrate material,including the steps of: a) feeding a first particulate material with afeeder to a first moving endless surface with a plurality of reservoirs,adjacent said feeder; b) allowing flow of said particulate material, orpart thereof, into a volume space present between said first movingendless surface and a three-dimensional plate, adjacent said feeder andadjacent and opposing said first moving endless surface; and contactinga part of said particulate material with said three dimensional plate,said plate having a first plate face adjacent said first moving endlesssurface, and said plate face having: i) a first surface areasubstantially parallel to said first moving endless surface; and ii) asecond surface area neighboring said first surface area, beingdownstream (in MD) from said first surface area, said second surfacearea being non-parallel to said first moving endless surface and leadingfrom said first surface area towards said first moving endless surface,said first surface area and said second surface area are connected toone another under an angle, and said second surface area having anaverage angle with said first moving endless surface from about 10° toabout 80°; c) applying a pressure with said plate onto at least aportion of said particulate material present between said first plateface and said first moving endless surface, guiding said material intosaid reservoirs; d) transferring said particulate material in saidreservoirs of said first moving endless surface directly or indirectlyto a second moving endless surface, being, or carrying, said substratematerial; and e) depositing said particulate material onto saidsubstrate material.
 2. A method according to claim 1, wherein saidpressure application step c) includes: firstly applying a pressure, withsaid first surface area of said plate, said pressure being substantiallyperpendicular to the direction of movement of the first moving endlesssurface (MD), thereby guiding at least a first portion of saidparticulate material into said reservoirs; and secondly, applying apressure with said plate face's second surface area, said pressure beingnon-perpendicular to the direction of movement of the first movingendless surface (MD), thereby guiding at least a second portion of saidparticulate material into said reservoirs.
 3. A method according toclaim 1, wherein said plate face has a third surface area substantiallyparallel to the first moving endless surface and in close proximitythereto than said first surface area, said third surface area guiding athird portion of said particulate material into said reservoirs and/oraiding retention of said particulate material in said reservoirs.
 4. Amethod according to claim 1, wherein the pressure is controlled by useof a pressure control means, including an actuator.
 5. A methodaccording to claim 1, wherein said first moving endless surface has asurface speed of at least about 2 m/s.
 6. A method according to claim 5,wherein said first moving endless surface has a surface speed of atleast about 3 m/s.
 7. A method according to claim 6, wherein said firstmoving endless surface has a surface speed of at least about 4.5 m/s. 8.A method according to claim 7, wherein said first moving endless surfacehas a surface speed of at least about 6.0 m/s.
 9. A method according toclaim 8, wherein said first moving endless surface has a surface speedof at least about 7.0 m/s.
 10. A method according to claim 1, whereinsaid first moving endless surface has a speed of at least about 1000parts per minute.
 11. A method according to claim 1, wherein saidparticulate material has a mass median particle size from about 150microns to about 1000 microns.
 12. A method according to claim 11,wherein said particulate material has a mass median particle size fromabout 200 microns to about 700 microns.